1. Field of the Invention
The present invention relates generally to the field of Personal Area Networks (PANs), in particular Wireless PANs (WPANs), and Wireless Sensor Networks (WSNs). More particularly, the present invention concerns a radio coverage extender for a WPAN or WSN node, like a ZigBee node, embedded in a user communications terminal such as a mobile phone, a smartphone or the like.
2. Description of the Related Art
WPANs, WSNs and similar networks are gaining importance because they allow offering a new breed of value-added services to users. Bluetooth (IEEE standard 802.15.1) and ZigBee (IEEE standard 802.15.4) are examples of standards for WPANs and WSNs that became popular in the last years.
In particular, ZigBee transceivers are regarded with interest because of their low power consumption and the capability of ZigBee nodes to self configure themselves in an “ad-hoc” network, thereby allowing an indirect transfer of data from a node to another. In addition to this, the possibility of integrating in a single chip both the analogue transceiver front-end and the functionalities for managing the complete communication protocol enables embedding ZigBee nodes within smart-card devices like Subscriber Identity Modules (SIMs) used in mobile communications terminals like mobile phones operable in GSM (General System for Mobile communications) and UMTS (Universal Mobile Telecommunications System) networks, and Multi Media Cards (MMCs).
The integration of wireless communication interfaces within SIM cards is already known in the art.
For example WO 01/95605 discloses a system including a SIM module with a conventional GSM SIM card connected to a Bluetooth slave unit, and a GSM terminal including a Bluetooth master unit. Communication of the SIM with the terminal takes place through the Bluetooth units.
EP 1738602 and EP 1815407 disclose a SIM card for a mobile terminal operable in a mobile network, the SIM card incorporating a radio transceiver module intended for communications that do not pass through the mobile network. In this way, a ZigBee-SIM (Z-SIM) is obtained, i.e. a SIM card that embeds a ZigBee node capable of interacting with WPANs and thus enabling offering new value-added services to the end user; moreover, the integration in the SIM card of a ZigBee node allows the user to maintain the connectivity functionalities to WPAN networks even when changing the mobile phone.